FIELD NATURALISTS' CLUB. 29 



Spore formation has not yet been observed in all bacteria, 

 hence one of the chief difficulties in the way of a scientific 

 classification. 



Spores are invested with a thick membrane and are far more 

 resistent to the action of chemical reagents and heat than the 

 parent colls. They also retain their vitality when dried. This is 

 a point of great practical importance. To destroy spore.;, infecl i 1 1 

 articles such as clothes must he raised to a much higher 

 temperature than that necessary to destroy bacteria. Again, in 

 the preparation of sterilized media, the test tubes must be heated 

 onseveral consecutive days in order to kill successive crops of spores. 



It is probable that spore formation is not due to exhaustion 

 of the nourishing soil and consequent provision for the perpetuation 

 of the species as lias been supposed by some. It is more likely 

 that it is a result of free access of oxygen. 



Anthrax bacilli have been found in the soil where bodies of 

 animals dead of anthrax have been buried, and thus a real danger 

 to the community arises. Klein, however, has pointed out that 

 if mice and guinea pigs which have died of anthrax are kept 

 unopened, the bacilli degenerate and disappear. Infection of a 

 burial ground must therefore result from the interment of bodies 

 of animals in which necropsies have been made, or in which the 

 hides have been soiled with excretions or blood. The practical 

 lesson to be learned is the same in either case, that all animals 

 dead of any suspicious disease should be at once cremated. 



I may state here that a series of observations which I made 

 on the earth over the graves of lepers or where pieces of leprous 

 tissue had been interred gave negative results. 



The classification of bacteria like that of many other groups 

 of plants and animals is still in a transition state, but pro- 

 visionally the classification suggested by Zopf may be accepted as 

 a good one for working purposes. 



He divides the Schizomycetes as follows : 



3. Vibrio. 



4. Leuconostoc. 



5. Bacillus. 



6. Clostridium. 

 Group III. — Leptotrichete. — Cocci, 



rods and thread forms. Dis- 

 tinction between base and apex 

 in latter. 



Genus i. Leptothrix. 

 2. Beggiatoa. 



rods and thread-forms. No dis-l 3. Crenothrix. 



tinction between base and a] 4. Phragmidiothrix. 



in latter. Fission in one direc- Group W.—Cladstrichcece. — Cocci, 

 tion. : rods, spirals and thread forms. The 



Genus 1 Bacterium. latter with false branchings. 



2. Spirillum. Genus 1. Cladsthrix. 



Group I. — Ccccacece. — Cocci and 

 thread-forms resulting from jux- 

 taposition of cocci. Fiss.on in 

 one or more directions. 



Genus 1. Streptococcus. 



2. Micrococcus. 



3. Merismopedia. 



4. Sarcina. 



5. Ascococcus. 

 Group II. — Harfcriacca. — Cocci, 



